Vacuum pumps are component of among the final procedures in the repair process. After you’ve diagnosed and repaired any leaks or additional issues in the machine it’s time to recharge. Before recharging you wish to make sure the system is free from any 
undesired gasses, air, or water. If they were to stay in the system, it could turn the oil it runs on into sludge and leave behind damaging impurities.
The draw on a vacuum pump is usually divided into its “CFM,” or Cubic Feet each and every minute. To estimate what your CFM requirements, look at the tonnage of the systems you focus on. Take the sq . root of that number and you’ll get the approximate CFM you need to have to work with that system. Typical Ac Vacuum Pump residential systems need 4-5 CFM, while industrial and rooftop systems generally require as much as 6-8 CFM.